Kevin Mitnick, one of the most famous hackers in the history of cybersecurity, died over the weekend at age 59 after a more than year-long battle with pancreatic cancer, his family said in a published obituary.

Before his death on July 16, Mitnick’s hacking sprees were legendary, and multiple films were inspired by him.

The first, “WarGames” starring Matthew Broderick, was partially based on allegations that Mitnick successfully hacked the computer systems at North American Aerospace Defense Command as a teenager. He denied ever having done so.

Mitnick’s restless curiosity caught up with him when he was arrested for stealing $1 million in proprietary software from Digital Equipment Corporation in 1988. Mitnick was sentenced to a year in prison and three years of probation, but a new arrest warrant was issued in 1995 for violating that probation. Mitnick went on the run, breaking into the computer systems of multiple corporations, cell phone companies, and educational institutions, according to the federal indictment against him.

Through it all, Mitnick and his defenders insisted he was harmless, not actually trying to hurt anyone or pursue financial gain.

“I was an old-school hacker, doing it for intellectual curiosity,” Mitnick told Wired magazine in a 2008 interview. But federal authorities were so concerned about his capabilities that when he was incarcerated again in 1995, Mitnick told CNN he was held in solitary confinement for a time out of concern that even proximity to a telephone could allow him to continue hacking.

Mitnick and federal prosecutors agreed to a plea deal in 1999 to seven criminal counts, including wire fraud and causing damage to computers. The deal included a 46-month prison sentence and a ban on being “employed in any capacity wherein he has access to computers or computer-related equipment or software” during a period of probation, but he was released in 2000 due to credit for time already served.

Mitnick published a memoir on his hacking career, “Ghost in the Wires: My Adventures as the World’s Most Wanted Hacker,” in 2011.

Following his prison term, Mitnick became a white-hat hacker, using his expertise to legally help businesses track people trying to break into their systems. For the past decade, he was the chief hacking officer and partial owner of the tech security firm KnowBe4, founded by his close friend and business partner, Stu Sjouwerman.

CNN